LIQUID CLEANING PRODUCTS

Abstract: A very stable, pourable and easy to process substantially non-aqueous liquid detergent composition is provided comprising a liquid phase and a particulate solid phase dispersed therein, said solid phase comprising from 10 to 60 % by weight of sodium metasilicate and from 0.1 to 10 % by weight of a hydrophobically modified silica, both concentration ranges mentioned being based on the total weight of the detergent composition, said sodium metasilicate containing less than 8 % by weight of water.

Description: LIQUID CLEANING PRODUCTS FIELD OF INVENTION The present invention relates to liquid non-aqueous cleaning products, especially substantially non-aqueous liquid detergent compositions containing particulate solid materials. Substantially non-aqueous liquids are those containing little or no water. PRIOR ART AND BACKGROUND OF THE INVENTION Non-aqueous detergent liquids have been proposed for a number of uses, such as fabric washing and dishwashing. They have advantages over powder products in that they are more rapidly dispersed in water. Further advantages over powder products are the possibility of automatic dosing and higher obtainable product densities, resulting in lower transportation and packaging costs. Non-aqueous detergent liquids have advantages over aqueous liquid products in that they are capable of including water-sensitive ingredients such as bleaches. With regard to the use in industrial washing machines of non-aqueous liquid detergent compositions containing a particulate solid phase dispersed in a liquid phase, it is important that the viscosity of such compositions should be as low as possible whilst still maintaining acceptable stability against separation of the suspended particulate solid material. The reason is that products used in industrial washing machines are usually pumped through long supply lines from the dosing equipment to the point of use inside the washing machine. It has been described in WO 91/12313 that non-aqueous liquid detergent compositions comprising sodium metasilicate, having an improved stability against sedimentation of the particulate solid material suspended therein and having a reduced tendency to clear layer separation upon storage, can be formulated by including therein a metal oxide having a bulk density of 200 to 1000 g/1. Furthermore, WO 91/12312 relates to a non-aqueαus liquid cleaning product comprising particles of solid material dispersed in a solvent, a deflocculant material, and a hydrophobically modified silica containing dispersant, whereby the stability of the product is shown to be improved by said dispersant. This patent document does, however, not disclose non-aqueous liquid compositions containing considerable amounts of alkaline material, such as sodium metasilicate, which are contained in the non- aqueous liquid composition according to the present invention. Detergent compositions suitable for use in industrial washing machines generally contain a considerable level of material which gives a high alkalinity in the wash liquor. This type of material is often referred to as either buffer salt or alkalinity booster. It is known that sodium metasilicate may effectively perform the function of both builder material and alkalinity booster. Therefore, sodium metasilicate is a preferred component of industrial detergent products. However, we have found that only anhydrous sodium metasilicate as a constituent of a non-aqueous liquid composition has resulted in a non-aqueous liquid with an acceptable viscosity so that it can be dosed without having to use complicated apparatus. Moreover, an acceptable viscosity of such non-aqueous liquids containing anhydrous sodium metasilicate could only be obtained at relatively low levels of particulate solids dispersed therein. In this respect, it has been disclosed by European Patent Application No. 92 203 446.7 that the incorporation of a special type of anhydrous sodium metasilicate, i.e. substantially amorphous metaslicate, results in a low viscosity, pourable, easy-to-process formulation. It has, furthermore, been described in this document that the use of anhydrous substantially amorphous sodium metasilicate as a component of non-aqueous liquids allows a larger amount of solids to be incorporated for obtaining formulations with a good viscosity and stability. Although the stability improvement disclosed by this document is significant, a further stability improvement is considered to be.desirable because of the resulting better storage stability of the non-aqueous liquid concerned. In view of the foregoing, it is an object of the present invention to provide a non-aqueous liquid detergent composition having a good viscosity and stability against sedimentation, and containing considerable amounts of anhydrous sodium metasilicate. It has now, surprisingly, been found that this object could be achieved by including in said non-aqueous liquid composition, a hydrophobically modified silica ontaining dispersant. DEFINITION OF THE INVENTION The present invention provides a substantially non-aqueous liquid detergent composition comprising a liquid phase and a particulate solid phase dispersed therein, said solid phase comprising from 10 to 60% by weight of sodium metasilicate and from 0.1 to 10% by weight of a hydrophobically modified silica containing dispersant, both concentration ranges being based on the total weight of the composition, said sodium metasilicate containing less than 8% by weight of water. The present invention also relates to the use of hydrophobically modified silica as a stabilising agent in a substantially non-aqueous liquid detergent composition comprising sodium metasilicate, said metasilicate containing less than 8% by weight of water. DETAILED DESCRIPTION OF THE INVENTION All compositions according to the present invention are substantially non-aqueous liquid cleaning products. In the context of this specification, all references to liquids refer to materials which are fluid at 25°C at atmospheric pressure. The compositions are substantially non-aqueous, i.e. they contain little or no free water, generally less than 10% by weight, preferably less than 3% by weight, more preferably less than 1% by weight. It has been found that the higher the water content, the more likely it is for the viscosity to be too high, or even for setting to occur. Setting is characterised by an increase in product viscosity during storage as a result of the reversible build-up of a structure within the non-aqueous liquid with time. Setting could eventually result in a product which cannot be poured or pumped without prior shaking or stirring. Preferably, compositions of the invention have a viscosity of less than 2,500 mPa.s at a shear rate of 21 S _1 , a viscosity range of 500-2,000 mPa.s being more preferred (as measured on a Haake rotoviscometer RV20 with a mv2p head at 25°C after 5 minutes) . Most preferably, the viscosity is in between 1000 and 2000 mP.s at 21 S "1 , as measured using the same method. The compositions according to the invention may be formulated in a very wide range of specific forms according to the intended use. They may be formulated as cleaners for hard surfaces (with or without abrasive) or as agents for warewashing either by hand or by mechanical means. They may also be formulated as agents for washing and/or conditioning of fabrics. Those last-mentioned products constitute an especially preferred form of the present invention because in that role there is a very great need to be able to incorporate substantial amounts of various kinds of solids. These compositions may be of the kind used for pre-treatment of fabrics with the composition, neat or diluted, before they are rinsed or subjected to a main wash. The compositions may also be formulated as main wash products, being dissolved and/or dispersed in the water with which the fabrics are contacted. Thus the compositions will contain at least one agent which promotes the cleaning and/or conditioning of the article(s) in question, selected according to the intended application. Usually, this agent will be selected from surfactants, enzymes, bleaches, microbiocides (for fabrics) fabric softening agents and (in the case of hard-surface cleaning) abrasives. Of course, in many cases more than one of these agents will be present, as well as other ingredients commonly used in the relevant product form. The sodium metasilicate The concentration of sodium metasilicate in a non-aqueous liquid detergent composition according to the invention is generally in the range of 10-60% by weight, preferably 25-55% by weight, more preferably 30-55% by weight, of the composition. The type of sodium metasilicate applied in compositions of the invention is substantially anhydrous sodium metasilicate which most preferably consists of sodium oxide, silicon dioxide, about 0-3 % by weight of carbon dioxide, and about 2-3% by weight of water, whereby the molar ratio of sodium oxide to silicon dioxide is in the range from 0.8 to 1.2. This type of sodium metasilicate typically consists of 50.5±2.0% by weight of sodium oxide, 45.5±2.0% by weight of silicon dioxide, 1.5% by weight of carbon dioxide and 2.5% by weight of water. The water content of the sodium metasilicate (as analysed by heating a sample up to 600°C for 1 hour) should not exceed an upper level of 8% by weight, more preferably 5% by weight, a maximum water content of 3% by weight being most preferred. The type of sodium metasilicate applied in the non-aqueous liquid composition of the invention is, preferably, substantially crystalline sodium metasilicate. This type of sodium metasilicate may contain at most 10% by weight, preferably 1% by weight of amorphous sodium metasilicate having no crystalline order. In this context, substantially crystalline sodium metasilicate is defined as material that shows at most 10% by weight of said material having no crystalline order when applying X-ray crystallography techniques. The liquid and solid phase • Preferably, the detergent compositions of the invention contain the liquid phase in an amount of at least 10% by weight of the total composition. The amount of the liquid phase present in the composition may be as high as about 90% by weight, but in most cases the practical amount will lie between 20 and 70% and preferably between 35 and 50% by weight of the composition. Preferably, the liquid phase comprises liquid nonionic surfactant. For use in fabric washing and carpet washing, the liquid phase preferably contains from 30 to 50% by weight of liquid nonionic surfactant. For use in mechanical dishwashing, lower liquid nonionic surfactant levels are generally applied, typically less than 10% by weight, preferably between 1 and 3% by weight of the total formulation. The rest of the liquid phase may in this case contain a solvent as described below. The total solids content of compositions according to the invention is generally in the range of from 10 to 90%, but in most cases the practical total solids conteηt will be in the range of from 30 to 80% by weight of the total composition, a range of from 50 to 65% by weight being more preferred. Most preferably, the total solids content does not exceed 40% by volume of the total composition. The solid phase is generally in particulate form and usually has a weight average particle size of less than 300 microns, preferably less than 200 microns, more preferably less than 100 microns, especially less than 10 microns. The particle size may even be of sub-micron size. The proper particle size can be obtained by using materials of the appropriate size or by milling the total product in a suitable milling apparatus. Hydrophobically modified silica Compositions of the invention comprise hydrophobically modified (HM) silica as a dispersant material. For the purpose of the present invention, a dispersant material is a material whose main purpose is to stabilise the composition. Furthermore, HM-dispersant materials, such as HM-modified silica, are particulate materials, of which the outer surface has been chemically treated to reduce the hydrophilic nature thereof. Preferably, the number of hydroxy and/or acid groups at the surface of the HM silica particles is reduced by a hydrophobing treatment. Suitable reactions include esterification or etherification of the hydrophilic groups present at the outer surface of the particles. Preferably, the hydrophobing treatment involves at least 10%, more preferably from 40 to 95%, most preferably from 50 to 90%, of these hydrophilic groups. Partial hydrophobing is preferred over complete hydrophobation. The hydrophobation of the silica particles preferably involves the substitution of the free hydroxy groups at the outer surface thereof by less hydrophilic groups. More preferably, the surface hydroxy groups are substituted by short alkyl groups, e.g. by methyl groups. Preferred HM silica-containing dispersant materials have a weight average particle size of from 0.005 to 10 microns, more preferably 0.01 to 5 microns, most preferably 0.01 to 3 microns. The level of HM silica-dispersant material is suitably from 0.1 to 10% by weight, preferably 0.3 to 5% by weight, more preferably 0.5 to 3% by weight of the composition. Surfactant material Particularly when intended to be used for fabric washing, the non-aqueous liquids of the invention will generally contain one or more surfactant agents. Where surfactants are solids, they will usually be dispersed or dissolved in the liquid phase. Where they are liquid, they will usually constitute all or part of the liquid phase. However, in some cases the surfactants may undergo a phase change in the composition. In general, surfactants for use in the compositions of the invention may be chosen from any of the classes, sub¬ classes and specific materials described in "Surface Active Agents", Vol. I, by Schwartz & Perry, Interscience 1949 and "Surface Active Agents", Vol. II, by Schwartz, Perry & Berch (Interscience 1959) , in the current edition of "McCutcheon's Emulεifiers & Detergents" published by the McCutcheon division of Manufacturing Confectioners Company or in "Tensid-Taschenbuch" , H. Stache, 2nd Edn. , Carl Hanser Verlag, Mϋnchen & Wien, 1981. In respect of all surfactant materials, but also with respect to all ingredients described herein as examples of components in compositions according to the present invention, unless the context requires otherwise, the term "alkyl" refers to a straight or branched alkyl moiety having from 1 to 30 carbon atoms, whereas "lower alkyl" refers to a straight or branched alkyl moiety of from 1 to 4 carbon atoms. These definitions refer to alkyl species however incorporated (e.g. as part of an aralkyl species) . Nonionic surfactants The preferred type of detergent surfactant present in non- aqueous liquids of the invention is nonionic surfactant. Nonionic detergent surfactants are well known in the art. They normally consist of a water-solubilising polyalkoxylene or a mono- or di-alkanolamide group in chemical combination with an organic hydrophobic group derived, for example, from alkylphenols in which the alkyl group contains from about 6 to about 12 carbon atoms, dialkylphenols in which each alkyl group contains from 6 to 12 carbon atoms, primary, secondary or tertiary aliphatic alcohols (or alkyl-capped derivatives thereof) , preferably having from 8 to 20 carbon atoms, monocarboxylic acids having from 10 to about 24 carbon atoms in the alkyl group and polyoxy propylenes. Also common are fatty acid mono- and dialkanolamides in which the alkyl group of the fatty acid radical contains from 10 to about 20 carbon atoms and the alkyoyl group having from 1 to 3 carbon atoms. In any of the mono- and di- alkanolamide derivatives, optionally there may be a polyoxyalkylene moiety joining the latter groups and the hydrophobic part of the molecule. In all polyalkoxylene containing surfactants, the polyalkoxylene moiety preferably consists of from 2 to 20 groups of ethylene oxide or ethylene oxide and propylene oxide groups. Among the latter class, particularly preferred are those described in Applicants' published European specification EP-A-225, 654 , especially for use as all or part of the liquid phase. Also preferred are those ethoxylated nonionics which are the condensation products of fatty alcohols with from 9 to 15 carbon atoms condensed with from 3 to 11 moles of ethylene oxide. Examples of these are the condensation products of C 11 _ 13 alcohols with (say) 3 to 7 moles of ethylene oxide. These may be used as the sole nonionic surfactant or in combination with those described in the last-mentioned European specification, especially as all or part of the liquid phase. Another class of.suitable nonionics comprise the alkyl polysaccharides (polyglycosides/oligosaccharides) such as described in any of specifications US-A-3,640,998; US-A-3,346,558; US-A-4,223,129; EP-A-92,355; EP-A-99,183. Mixtures of different nonionic detergent surfactants may also be used. Mixtures of nonionic detergent surfactants with other detergent surfactants such as anionic, cationic or ampholytic detergent surfactants and soaps may also be used. Generally, the level of nonionic surfactants is from 10 to 90% by weight of the composition, preferably from 20 to 70%, most preferably from 35 to 50% by weight. Anionic surfactants Examples of anionic detergent surfactants suitable to be included in compositions according to the present invention, are alkali metal, alkaline earth metal, ammonium or alkylol amine salts of alkylbenzene sulphonates having from 10 to 18 carbon atoms in the alkyl group, alkyl and alkylether sulphates having from 10 to 24 carbon atoms in the alkyl group, the alkylether sulphates having from 1 to 5 ethylene oxide groups, and olefin sulphonates prepared by sulphonation of C 10 _ 24 alpha-olefins and subsequent neutralisation and hydrolysis of the sulphonation reaction product. Preferably, the level of anionic surfactants is in between 1 and 15% by weight of the composition, more preferably between 2 and 10% by weight. Before incorporation, all anionic surfactants will either be liquid, in which case, in the composition they will constitute all or part of the liquid phase, or .they will be solid, in which case, in the composition they will either be dispersed in the liquid phase or they will be dissolved therein. Thus as used herein, the term "solids" is to be construed as referring to materials in the solid phase which are added to the composition and are dispersed therein in solid form, those solids which dissolve in the liquid phase and those in the liquid phase which solidify (undergo a phase change) in the composition, wherein they are then dispersed. Detergency builders In addition to the above-described sodium metasilicate, the detergency builder present in compositions according to the invention may include any material capable of reducing the level of free calcium and magnesium ions in the wash liquor and will preferably provide the composition with other beneficial properties such as the generation of an alkaline pH and the suspension of soil removed from the fabric. The level of the total amount of detergency builder including sodium metasilicate present in compositions according to the invention may be from 10 to 70% by weight, preferably from 30 to 60% by weight. Suitable builders comprise both inorganic and organic builders. They may also be subdivided into the phosphorus- containing and non-phosphorus types, the latter being preferred when environmental considerations are important. In general, the inorganic builders comprise the various phosphate-, carbonate-, silicate-, borate- and aluminosilicate-type materials, particularly the alkali metal salt forms. Mixtures of these may also be used. Examples of phosphorus-containing inorganic builders, when present, include the water-soluble salts, especially alkali metal pyrophosphates, orthophosphates, polyphosphates and phosphonates. Specific exam.RT.es of inorganic phosphate builders include sodium and potassium tripolyphosphates, phosphates and hexametaphosphates. Examples of non-phosphorus-containing inorganic builders, when present, include water-soluble alkali metal carbonates, bicarbonates, borates, silicates, and. crystalline and amorphous silicates. Specific examples include sodium carbonate (with or without calcite seeds) , potassium carbonate, sodium and potassium bicarbonates, and zeolites. Examples of suitable organic builders include the alkali metal, ammonium and substituted ammonium, citrates, succinates, malonates, fatty acid sulphonates, carboxymetoxy succinates, ammonium polyacetates, carboxylates, polycarboxylates, aminopolycarboxylates, polyacetyl carboxylates and polyhydroxy sulphonates. Specific examples include sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylene diamine tetraacetic acid, nitrilotriacetic acid, oxydisuccinic acid, melitic acid, benzene polycarboxylic acids and citric acid. Other examples are organic phosphonate-type sequestering agents such as those sold by Monsanto under the tradename of the Dequest range. Other suitable organic builders include the higher molecular weight polymers and co-polymers known to have builder properties, for example appropriate polyacrylic acid, polymaleic acid and polyacrylic/polymaleic acid copolymers and their salts, particularly those sold by BASF under the Sokalan Trade Mark. Other examples of suitable organic builders of this type are acrylate/methacrylate copolymers and homopolymers which may also be added as stabilisers against sedimentation and for anti-ashing and anti-redeposition purposes. The bleach system It was found that very stable bleach-containing, substantially non-aqueous liquid detergent compositions could be obtained when applying the afore-described hydrophobically modified silica as a constituent thereof. Bleaches which are suitable for non-aqueous compositions of the invention include the halogen, particularly chlorine bleaches such as provided in the form of alkali metal hypohalites, e.g. hypochlorites. Particularly in the application of fabrics washing, the oxygen bleaches are preferred, for example in the form of an inorganic persalt, preferably with a bleach precursor, or as a peroxy acid compound . In the case of the inorganic persalt bleaches, the activator makes the bleaching more effective at lower temperatures, i.e. in the range from ambient temperatures to about 60°C, so that such bleach systems are commonly known as low-temperature bleach systems. They are well known in the art. The inorganic persalt, such as sodium perborate monohydrate, acts to release active oxygen in solution, and the activator is usually an organic compound having one or more reactive acyl residues, which cause the formation of peracids, the latter providing for a more effective bleaching action at lower temperature than the peroxybleach compound alone. The ratio by weight of the peroxybleach compound to the bleach activator is generally from about 20:1 to about 1:1, preferably from about 10:1 to about 2:1, most preferably from 5:1 to 3.5:1. Whilst the amount of the bleach system, i.e. peroxybleach compound and activator, may be varied between about 5% and about 35% by weight of the total non- aqueous liquid, it is preferred to use from about 6% to about 30% by weight of the ingredients forming the bleach system. Thus the preferred level of the peroxybleach compound in the composition is between about 5.5% and about 27% by weight, while the preferred level of the activator is between about 0.5% and 14% by weight, most preferably between about 1% and about 5% by weight. Typical examples of suitable peroxy bleach compounds are alkali metal perborates, both tetrahydrates and monohydrates, alkali metal percarbonateε, persilicates and perphosphates, of which sodium perborate and, particularly, sodium percarbonate are preferred. Preferred activator materials are TAED and glycerol triacetate. It is particularly preferred to include in the compositions of the invention containing a bleach or bleach system, a stabiliser for the bleach or bleach system, for example ethylene diamine tetramethylene phosphonate and diethylene triamine pentamethylene phosphonate or other appropriate organic phosphonate or salt thereof, such as the Dequest range hereinbefore described. These stabilisers can be used in acid or salt form, such as the magnesium, calcium, zinc or aluminium salt form. The stabiliser may be present at a level of up to about 1% by weight, preferably between about 0.1 and about 0.5% by weight. The deflocculant Preferably, compositions of the invention also comprise a deflocculant material. In principle, any material may be used as a deflocculant provided that it fulfils the deflocculation test described in EP-A-266,199 (Unilever). The capability of a substance to act as a deflocculant will partly depend on the solids/liquid phase combination. Especially preferred deflocculants are acids. Some typical examples of deflocculants include the alkanoic acids such as acetic, propionic and stearic acid and their halogenated counterparts such as trichloroacetic and trifluoracetic as well as the alkyl (e.g. metharie) sulphonic acids and aralkyl (e.g. paratoluene) sulphonic acids. Examples of suitable inorganic mineral acids and their salts are hydrochloric, carbonic, sulphurous, sulphuric, and phosphoric acids; potassium monohydrogen sulphate, sodium monohydrogen sulphate, potassium monohydrogen phosphate, potassium dihydrogen phosphate, sodium monohydrogen phosphate, potassium dihydrogen pyrophosphate. Other organic acids may also be used as deflocculants, for example formic, lactic, amino acetic, benzoic, salicylic, phthalic, nicotinic, ascorbic, ethylene diamine tetraacetic, and aminophosphonic acids, as well as longer- chain fatty carboxylates and triglycerides, such as oleic, stearic, lauric acid and the like. Peracids, such as percarboxylic and persulphonic acids, may also be used. "Fatty" anions are very suitable deflocculants, and a particularly preferred class of deflocculants comprises anionic surfactants. Although anionics which are salts of alkali or other metals may be used, particularly preferred are the free acid forms of these surfactants (wherein the metal cation is replaced by an H + -cation, i.e. proton) . These anionic surfactants include all those classes, sub¬ classes and specific forms described in the afore-mentioned general references on surfactants, viz. Schwartz & Perry, Schwartz Perry and Berch, McCutcheon's, Tensid-Taschenbuch. Many anionic surfactants have already been described hereinbefore. In the role of deflocculants, the free acid forms of these are generally preferred. In particular, some preferred sub-classes and examples are the C 10 -C 22 fatty acids and dimers thereof, the.C 8 _ c 18 alkylbenzene sulphonic acids,the C 10 -C 18 alkyl or alkylether sulphuric acid monoesters, the C 12 -C 18 paraffin sulphonic acids, the fatty acid sulphonic acids, the benzene, toluene, xylene, and cumene sulphonic acids and so on. The level of the deflocculant material in the composition can be optimised by the means described in the afore- mentioned EP-A-266,199, but in very many cases this level is at least 0.01%, usually 0,1% and preferably at least 1% by weight, and may be as high as 15% by weight. For most practical purposes, the amount ranges from 1-12%, preferably from 2-6% by weight, based on the total non- aqueous composition. The antifoaming agent In view of the foaming behaviour of compositions according to the invention, good results with respect to foam reduction were obtained when using a combination of a hydrocarbon wax and an alkyl phosphate as an anti-foaming agent. It appeared that good defoaming characteristics can be obtained after both separate and combined addition of these compounds to a composition of the invention. Alternatively, silicone oil based compositions containing high and low viscosity oil, particularly high-viscosity silicone oil with a viscosity greater than 10000 Mp.s at 25°C and a shear rate of 21 S "1 , may be effectively used as antifoaming agents. Miscellaneous other ingredients Other ingredients which may be present in compositions of the invention comprise those remaining ingredients which may be used in liquid cleaning products. Examples are fabric conditioning agents, enzymes, perfumes (including deoperfumes) , microbiocides, coloring agents, fluorescers, soil-suspending agents (anti-redeposition agents) , corrosion inhibitors, enzyme-stabilising agents, and lather depressants. Amongst the fabric conditioning agents which may be used, either in fabric washing liquids or in rinse conditioners, are fabric softening materials such as fabric softening clays, quaternary ammonium salts, imidazolinium salts, fatty amines and cellulases. Enzymes which may be used in non-aqueous liquids according to the present invention include proteolytic enzymes, amylolytic enzymes and lipolytic enzymes (lipolases) . Various types of proteolytic enzymes and amylolytic enzymes are known in the art and are commercially available. They may be incorporated for instance as "prills", "marumes" or suspensions. The fluorescent agents which may be used in the non-aqueous liquid detergent products according to the invention are well known and many such fluorescent agents are available commercially. Usually, these fluorescent agents are supplied and used in the form of their alkali metal salts, for example, the sodium salts. The total amount of the fluorescent agent or agents used in composition of the invention is generally from 0.02-2% by weight. When it is desired to include anti-redeposition agents in a non-aqueous liquid of the invention, the amount thereof is normally from about 0.1% to about 5% by weight, preferably from about 0.2% to about 2.5% by weight of the total liquid composition. Preferred antiredeposition agents include carboxy derivatives of sugars celluloses, e.g. sodium carboxy ethyl cellulose, anionic polyelectrolytes, especially polymeric aliphatic carboxylates, or organic phosphonates. Use Compositions according to the present invention may be used for several detergency purposes, for example the cleaning of surfaces and the washing of fabrics. For the washing of fabrics, preferably an aqueous liquor containing from 0.1 to 10% by weight, more preferably 0.2 to 2% by weight, of the non-aqueous detergent composition of the invention is used. Processing During manufacture, it is preferred that all raw materials should be dry and (in the case of hydratable salts) in a low hydration state, e.g. anhydrous phosphate builder, sodium perborate monohydrate and dry calcite abrasive, where these are employed in the non-aqueous composition. In a preferred process, the dry, substantially anhydrous solids are blended with the liquid phase in a dry vessel. If deflocculant materials are used, these should preferably - at least partly - be mixed with the liquid phase, prior to the addition of the solids. In order to minimize the rate of sedimentation of the solids, this blend is passed through a grinding mill or a combination of mills, e.g. a colloid mill a corundum disc mill, a horizontal or vertical agitated ball mill, to achieve a particle size of 0.1 to 100 μm, preferably 0.5 to 50 μm, ideally 1 to 10 μm, as calculated by the D 3 2 measure. A preferred combination of such mills is a colloid mill followed by a horizontal ball mill since these can be operated under the conditions required to provide a narrow particle size distribution in the final non-aqueous liquid product. Of course, particulate material already having the desired particle size need not be subjected to this procedure and, if desired, can be incorporated during a later stage of processing. During this milling procedure, the energy input results in a temperature rise in the product and the liberation of air entrapped in or between the particles of the solid ingredients. It is, therefore, highly desirable to mix any heat-sensitive ingredients into the product after the milling stage and a subsequent cooling step. It may also be desirable to de-aerate the product before addition of these (usually minor) ingredients and optionally, at any other stage of the process. Typical ingredients which might be added at this stage are perfumes and enzymes, but might also include highly temperature sensitive bleach components or volatile solvent components which may be desirable in the final composition. However, it is especially preferred that volatile material be introduced after any step of de-aeration. Suitable equipment for cooling (e.g. heat exchangers) and de- aeration will be known to those skilled in the art. It follows that all equipment used in the process should preferably be completely dry, special care being taken after any cleaning operations. The same is true for subsequent storage and packing equipment. The invention is further illustrated by the following non- limiting Examples, in which parts and percentages are by weight unless otherwise stated. In the Examples the fol¬ lowing abbreviations are used: Vista Novel 1012.62: Nonionic surfactant, C 10#5 ethoxylated alcohol containing on average 6 EO groups per molecule, ex Vista Chemical Synperonic A3 Nonionic surfactant, C n ethoxylated alcohol containing on average 3 EO groups per molecule, ex ICI Marlon AS-3 The acid form of C 12 alkyl benzene sulphonic acid, ex Hϋls Alfl6/Wax 2:1 Defoaming agent consisting of alkyl phosphate and hydrocarbon wax, in a weight ratio of 2:1, ex Harcros/Ter Hell MgO Magnesium oxide, ex Merck SCMC Sodium Carboxy methyl cellulose, ex AKZO Sokalan CP7 Acrylic acid/maleic acid copolymer in the sodium salt form, ex BASF CaO Calcium oxide, ex Baker Chemical Co. Crystalline SMS crystalline sodium metasilicate, con¬ taining at most 4% of water, Simet AG, ex Rhone Poulenc Amorphous SMS amorphous sodium metasilicate, con¬ taining about 2-3% by weight of water, Vegomet, ex Montedison Sypernat D17 HM silica, ex Degussa Comparative Example A, Examples 1-3 The following non-aqueous detergent compositions (see Table 1) were prepared by mixing the ingredients in the order stated. It can be noted that the total solid phase level was slightly reduced when more HM silica (i.e. Sypernat D17) was included in the liquid composition. This is caused by the significantly lower density, and consequently higher specific volume of the Sypernat D17 as compared to crystalline sodium metasilicate. Sypernat D17 has a density of about 150 kg/m 3 , whereas the density of the crystalline applied SMS is roughly 1200 kg/m 3 . The ingredients were milled to give a mean particle size of 8 μm (by the D 3 2 measure) . The tendency of the composition to give clear layer separation was determined by filling a 500 ml tall polyethylene closable container with the composition, allowing it to stand without agitation for 4 weeks at 37°C and then measuring the height of any visible distinct upper layer. As can be noticed, this measure of the stability of each composition is shown in Table 1. The viscosities, as measured after one week using a Haake rotoviscometer at a shear rate of 21 s-l at 25°C after 5 minutes, of each composition are also given. After 4 weeks, at 37°C 18 3.5 Viscosity ( mPa.s) (measured at 21 S "1 ) 1700 1693 1984 1836 These results clearly show that the incorporation of hydrophobically modified silica increases the stability of non-aqueous liquid detergent formulations containing crystalline sodium metasilicate, without an unacceptable rise in the viscosity of such formulations. Comparative Example B, Example 4 In a similar manner to Examples A, 1-3, the following compositions were prepared. It can be seen from Table 2 that these compositions contain amorphous instead of crystalline sodium metasilicate. Thereafter, their stability as measured by their tendency to give clear layer separation and their viscosity were tested using the procedure described in Examples A, 1-3. The test results are shown in Table 2. After 4 weeks, at 37°C 11 Viscosity ( mPa.s) (measured at 21 S "1 ) 1260 1663 It can be seen that in this case a lower viscosity of the non-aqueous liquid product was found than when crystalline sodium metasilicate is applied. Furthermore, these results clearly indicate that a significant stability improvement (albeit slightly less pronounced than the improvement found in Examples A, 1-3) , can also be obtained when incorporating HM silica in a non- aqueous liquid detergent composition containing amorphous sodium metasilicate.

Claims: CLAIMS 1. A substantially non-aqueous liquid detergent composition comprising a liquid phase and a particulate solid phase dispersed therein, said solid phase comprising from 10 to 60% by weight of sodium metasilicate and from 0.1 to 10% by weight of a hydrophobically modified silica, both concentration ranges mentioned being based on the total weight of the detergent composition, said sodium metasilicate containing less than 8% by weight of water. 2. Composition according to Claim 1, wherein the solid phase comprises from 0.3 to 5% by weight, based on the total weight of the detergent composition, of hydrophobically modified silica. 3. Composition according to Claim 1 or 2, wherein the sodium metasilicate is substantially crystalline sodium metasilicate. 4. Composition according to any of Claims 1-3, wherein the sodium metasilicate contains less than 5% by weight of water. 5. Composition according to any of Claims 1-4, wherein the composition further comprises a peroxygen bleach compound. 6. Composition according to any of Claims 1-5, comprising from 20 to 70% by weight of a liquid phase and from 30 to 80% by weight of a solid phase. 7. Use of hydrophobically modified silica as a stabilising agent in a substantially non-aqueous liquid detergent composition comprising sodium metasilicate, said metasilicate containing less than 8% by weight of water.

Inventors: HORMANN JOSEPHUS MARIE, HOUGHTON MARK PHILLIP, VERHEUL RUDOLF CORNELIS S, HORMANN, JOSEPHUS, MARIE, HOUGHTON, MARK, PHILLIP, VERHEUL, RUDOLF, CORNELIS, S.
Applicants: UNILEVER NV, UNILEVER PLC, UNILEVER N.V.
Application year: 1994
Main classification: C11D17
IPC codes: C11D3, C11D17